Boiler- mind of its own!

[mivec]

I have just moved into a 2 year old house fitted with an ICOS boiler and Honeywell ST6400C progrsammer. During the night the boiler seems to fire up, the display shows demand for heat, even though- according to the programmer it should be switched off. No red lights are on and I am certain that the programmer is correctly set up and that the overide button has not been depressed.
The boiler is in the garage and I understand that the previous owner has said that it comes on occasionaly to stop it from freezing up.
Any view on this matter would be much appreciated.

 

[EliteHeat]

You probably have a frost stat installed.

The boiler does not have a mind of it's own - this is hard to do when the factory that made you pre-lobotomised it prior to delivery.

 

[mivec]

Thanks for your help and yes you are right, never come across one of these before! Anyway I adjusted it down to 3 degrees and it seems OK now. Thanks again.

 

[gas4you]

You should have a pipe stat in series with the frost stat, so the boiler will only fire when the return water temp drops.

 

[Gas2Air]

You should have a pipe stat in series with the frost stat, so the boiler will only fire when the return water temp drops.

Reminds of a job and the pipe stat was fitted on the gas pipe, been like that for 2 years.